feat(audio): add downloadable extra Piper voices with accents

Adds Alma (sv), Alan, Northern English, Cori, Alba (British/Scottish)
and Joe, John, Norman (American) as optional voices downloaded one at
a time from Settings, with gender (measured pitch) and accent shown in
the voice lists. The standard install is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/styles.css

@@ -4439,6 +4439,20 @@ select:focus {
   flex: 1;
 }
 
+.tts-download-list {
+  display: grid;
+  gap: 6px;
+}
+
+.tts-download-row {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  gap: 10px;
+  padding: 6px 0;
+  border-bottom: 1px solid var(--line, rgba(128, 128, 128, 0.2));
+}
+
 .track-layout-bar {
   display: flex;
   flex-wrap: wrap;